Here is a list of the webcomics on my RSS feed. I would add links but i'm really fucking lazy...
GU Comics - Okay for a single pane gaming related comic, I hardly read this to be honest.
Ctrl+Alt+Del - Used to be great, lost its way in the past couple of years but I still check up on it once in a while.
Dilbert - Nuff said.
Explosm.net - Mostly funny, sometimes really funny, sometimes awful. Completely dependent on who did the strip that day, but always completely tasteless... (the strip is actually called something else, but I can't remember and i'm at work at the moment so can't check.)
Penny Arcade - The quintessential gaming comic.
PvP - I find the author a bit of a twat, but the comic is usually funny.
Sinfest - Another one that used to be great but is a bit formulaic these days.
VG Cats - if they ever release a new comic...
XKCD - Geeky humour at it's very best.
Mal and Chad - A Calvin and Hobbes ripoff, I infrequently read this, mainly due to being a huge C&H fan and this is the closest thing.
Dark Legacy - Used to be funny when I played WoW, less funny these days as I no longer play
Questionable Content - Great, just great
The Perry Bible Fellowship - Only updated once in a very blue moon, but always funny.